Clarify Python command guidance

Author: dex-the-ai

README.md

@@ -43,9 +43,11 @@ cd src
 python3 -m pip install -r requirements.txt
 ```
 
+> Note: On Windows, or inside an activated virtual environment where `python3` is not available, use `python` in the commands below instead.
+
 > Note: Python SDKs older than version 4.1.9 require OpenSSL v1.1. This might not be the default in some newer platforms. In such scenarios, please install the SDK without using the prebuilt wheels
 
-> `python -m pip install couchbase --no-binary couchbase`
+> `python3 -m pip install couchbase --no-binary couchbase`
 
 > Refer to the [instructions in the SDK](https://github.com/couchbase/couchbase-python-client#alternative-installation-methods) for more info.